Automatically lockable cable rewinding structure

ABSTRACT

An automatically lockable cable rewinding structure includes an upper case having a first locating element; a lower case provided with a limiting recess; and a working member located between the two cases, and provided with a second locating element and a guide path for a rolling element to move therein. A length of cable is wound around the working member, and an elastic element is connected at two ends to the first and second locating elements. The limiting recess is formed at radially inner and outer ends with transverse inner and outer slits, respectively, and between the inner and the outer end with a longitudinal central slit, so that the rolling element is able to stably roll to and fro in the limiting recess along the central slit. Alternatively, the limiting recess and the guide path may be provided on the working member and the lower case, respectively.

FIELD OF THE INVENTION

The present invention relates to an automatically lockable cable rewinding structure, and more particularly to a cable rewinding structure that enables a cable wound therein to be smoothly pulled out and locked in place and smoothly rewound from a locked state simply by pulling and releasing the cable.

BACKGROUND OF THE INVENTION

Taiwanese New Utility Model Patent No. 414413 published on Dec. 1, 2000 discloses a cable rewinding box, which includes an upper cover, a lower cover, a rotating base, a rotating disc, a constant force spring, and a fixing shaft. With the constant force spring, the cable pulled out of the rewinding case may be automatically rewound. Generally speaking, the constant force spring may provide a relatively stable contractile tension, and can therefore protects the cable against damage and shortened usable life caused by exceeded tension. Since the constant force spring and the rotating disc are provided at different axial locations, the cable rewinding box may have a reduced overall height to enable convenient carrying thereof.

In addition to a two-way cable rewinding structure in which the cable may be pulled out in two opposite directions at the same time, there is also a one-way cable rewinding structure in which the cable can be pulled out in only one direction. The one-way cable rewinding structure includes a ball rolling in a guide path, and a spiral spring, so as to enable the function of pulling and rewinding a cable wound in the rewinding structure.

The following disadvantages are found in the above-mentioned conventional cable rewinding structures:

-   -   (1) A clearance must exist-between the ball and a limiting         recess. Due to the clearance, the ball is not able to regularly         move in the limiting recess and tends to skid off a locking         section in the guide path.     -   (2) When the ball fails to regularly and smoothly move in the         guide path, the spiral spring tends to gradually become fatigued         in its elastic strength, and the usable life of the cable is         adversely affected.     -   (3) When the ball fails to regularly and smoothly move in the         guide path, the guide path tends to become worn easily, and the         cable could not be smoothly rewound to adversely affect the         usable life thereof.

It is therefore tried by the inventor to develop an automatically lockable cable rewinding structure to overcome the above-mentioned problems existed in the prior art.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a cable rewinding structure that enables a cable wound therein to be smoothly pulled out and locked in place, and smoothly rewound from a locked state simply by pulling and releasing the cable.

Another object of the present invention is to provide a cable rewinding structure that includes a limiting recess with more than one slit, so that the limiting recess is able to interact with a rolling element in the cable rewinding structure.

A further object of the present invention is to provide a cable rewinding structure that enables a rolling element to roll in a guide path without causing easy wearing of the guide path.

A still further object of the present invention is to provide a cable rewinding structure, in which a guide path and a limiting recess thereof may be provided either on a lower case and a working member, respectively; or on the working member and the lower case, respectively.

A still further object of the present invention is to provide a cable rewinding structure that has simple structure.

A still further object of the present invention is to provide a cable rewinding structure, the operation of which would not cause any adverse influence on the usable life of the cable wound therein.

To achieve the above and other objects, the present invention provides an automatically lockable cable rewinding structure that includes an upper case provided with a first locating element; a working member provided with a second locating element, and a guide path for a rolling element to move therein; and a lower case provided on a bottom with a limiting recess. A length of cable is wound around the working member, and an elastic element is connected at inner and outer ends to the first and the second locating element. The limiting recess is formed at radially inner and outer ends with transverse inner and outer slits, respectively, and between the inner and the outer slit with a longitudinal central slit, so that the rolling element is able to stably roll to and fro in the limiting recess along the central slit. Alternatively, the limiting recess and the guide path may be provided on the working member and the lower case, respectively. With the cable rewinding structure of the present invention, cables may be conveniently and orderly collected and stored.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is an exploded perspective view of an automatically lockable cable rewinding structure according to a first embodiment of the present invention in an upside-down position;

FIG. 2 is an exploded perspective view of the automatically lockable cable rewinding structure of FIG. 1 in a normal position;

FIG. 3 is an assembled view of FIG. 1;

FIGS. 4A to 4C show the internal operation of the automatically lockable cable rewinding structure in the first embodiment when a cable is pulled out of the structure;

FIGS. 4D to 4E show the locking operation in the automatically lockable cable rewinding structure in the first embodiment when the outward pulled cable is released;

FIGS. 4F to 4G show the internal operation of the automatically lockable cable rewinding structure in the first embodiment when the released cable is rewound;

FIG. 5 is an exploded perspective view of an automatically lockable cable rewinding structure according to a second embodiment of the present invention in an upside-down position;

FIG. 6 is an exploded perspective view of the automatically lockable cable rewinding structure of FIG. 5 in a normal position;

FIG. 7 is an exploded perspective view of an automatically lockable cable rewinding structure according to a third embodiment of the present invention in an upside-down position;

FIG. 8 is an exploded perspective view of the automatically lockable cable rewinding structure of FIG. 7 in a normal position;

FIG. 9 is an assembled view of FIG. 8;

FIGS. 10A to 10C show the internal operation of the automatically lockable cable rewinding structure in the third embodiment when a cable is pulled out of the structure;

FIGS. 10D to 10E show the locking operation in the automatically lockable cable rewinding structure in the third embodiment when the outward pulled cable is released;

FIGS. 10F to 10G show the internal operation of the automatically lockable cable rewinding structure in the third embodiment when the released cable is rewound;

FIG. 11 is an exploded perspective view of an automatically lockable cable rewinding structure according to a fourth embodiment of the present invention in a normal position; and

FIG. 12 is an exploded perspective view of the automatically lockable cable rewinding structure of FIG. 11 in an upside-down position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 and 2 that are exploded perspective views of an automatically lockable cable rewinding structure according to a first embodiment of the present invention in an upside-down and a normal position, respectively; and to FIG. 3 that is an assembled view of FIG. 1. As shown, the automatically lockable cable rewinding structure in the first embodiment includes an upper case 11, a first elastic element 12, a rolling element 14, a length of cable 18, a working member 15, and a lower case 16.

The upper case 11 is provided on an inner side with an axially inward projected first locating element 111, and the lower case 16 is provided on an inner side with a guide path 161, along which the rolling element 14 moves. The guide path 161 is divided into a locking section 161 a, an inner path section 161 b, an outer path section 161 c, and a plurality of transition sections 161 d located at predetermined positions between the inner path section 161 b and the outer path section 161c. The locking section 161 a is adjacent to a beginning of the inner path section 161 b.

The working member 15 is provided on a peripheral wall at a predetermined position with a second locating element 151, and on a bottom at a predetermined position with a radially extended limiting recess 152. The first elastic element 12 is fixedly connected at an outer end to the second locating element 151 on the working member 15 and at an inner end to the first locating element 111 on the upper case 11. The limiting recess 152 is provided at radially inner and outer ends with transverse inner and outer slits 152 a, 152 c, respectively, and between the inner and outer ends with a longitudinal central slit 152 b, so that the rolling element 14 may stably roll to and fro in the limiting recess 152 along the central slit 152 b.

Please refer to FIGS. 2 and 3. To assemble the automatically lockable cable rewinding structure of the first embodiment, wind the cable 18 around the peripheral wall of the working member 15, such that the cable 18 may be pulled out of the rewinding structure in two opposite directions, and position the rolling element 14 in the limiting recess 152. When the working member 15 is connected to the lower case 16, make sure the rolling element 14 is seated in the guide path 161. Finally, fixedly connect the upper case 11 to the lower case 16. The inner, central, and outer slits 152 a, 152 b, 152 c are very important in the present invention. When the rolling element 14 rolls in the guide path 161 on the lower case 16, it upward presses against the limiting recess 152 at the same time. At this point, portions of the limiting recess 152 located at two opposite sides of the central slit 152 b produce two angular reaction forces that are applied to the rolling element 14 in two different directions, and the rolling element 14 is forced downward to press against the guide path 161 on the lower case 16. As a result, the rolling element 14 is able to move regularly. That is, with the three slits 152 a, b, and c, the rolling element 14 is restricted to roll to and fro only in the limiting recess 152, and the above-mentioned two angular reaction forces in two different directions may automatically change with a curvature of the guide path 161 to ensure that the rolling element 14 is able to stably move only between the limiting recess 152 and the guide path 161. Meanwhile, the inner and outer slits 152 a, 152 c together determine an extent by which the two angular reaction forces may be produced, and an extent by which the rolling element 14 may be pressed against the limiting recess 152. In other words, at the instant the rolling element 14 passes through the transition sections 161 d, moves into the locking section 161 a, or moves out of the locking section 161 a, the inner and outer slits 152 a, 152 c allow the portions of the limiting recess 152 at two opposite sides of the central slit 152 b to incline by an angle, which is sufficient to buffer the action force applied by the guide path 161 to the rolling element 14 without allowing the rolling element 14 to separate from the guide path 161. That is, the inclination of the portions of the limiting recess 152 at two opposite sides of the central slit 152 b is controlled by the inner and the outer slit 152 a, 152 c.

Moreover, the reaction forces produced by the portions of the limiting recess 152 at two sides of the central slit 152 b are of an elastic force. Therefore, the rolling element 14 rolling in the guide path 161 does not cause wearing of the guide path 161, but produces intermittent resistance. That is, the action force applied to the rolling element 14 automatically changes with the movement of the rolling element 14 when the same is in the transition sections 161 d.

With the above arrangements, the automatically lockable cable rewinding structure according to the first embodiment of the present invention is able to successfully lock or rewind the cable 18 through the following operating procedures.

(a) Pull Procedure 1:

-   -   Please refer to FIGS. 1, 2, and 4A at the same time.

It is noted the cable 18 can be pulled out of the assembled upper and lower cases 11, 16 in two opposite directions. When the cable 18 is pulled out in two opposite directions, the working member 15 is caused to turn counterclockwise, and the rolling element 14 is caused to move in the inner path section 161 b.

(b) Pull Procedure 2:

-   -   Please refer to FIGS. 1, 2, and 4B at the same time. When the         cable 18 is kept pulling out to turn the working member 15         counterclockwise, the rolling element 14 would move from the         inner path section 161 b through the transition sections 161 d         into the outer path section 161 c. At this point, the limiting         recess 152 at the bottom of the working member 15 functions to         restrict the rolling element 14 to smoothly move in the guide         path 161.     -   (c) Pull Procedure 3:     -   Please refer to FIGS. 1, 2, and 4C at the same time. When the         cable 18 is kept pulling out to turn the working member 15         counterclockwise, the rolling element 14 would move in the outer         path section 161 c.

(d) Lock Procedure 1:

-   -   Please refer to FIGS. 1, 2, and 4D at the same time. When the         cable 18 being pulled out in two opposite directions is         released, the working member 15 is guided by the first elastic         element 12 to turn clockwise, causing the rolling element 14 to         move from the outer path section 161 c through the transition         sections 161 d. At this point, the limiting recess 152 at the         bottom of the working member 15 functions to restrict the         rolling element 14 to smoothly move in the guide path 161 into         the locking section 161 a.

(e) Lock Procedure 2:

-   -   Please refer to FIGS. 1, 2, and 4E at the same time. When the         cable 18 being pulled out in two directions is released, the         rolling element 14 is affected by an elastic force of the first         elastic element 12 to stop in the locking section 161 a.

(f) Rewind Procedure:

Please refer to FIGS. 1, 2, and 4F at the same time. When the released cable 18 is slightly pulled out in two opposite directions, the working member 15 is caused to turn counterclockwise again, and the rolling element 14 is caused to move from the locking section 161 a through the transition sections 161 d into the inner path section 161 b. At this point, the limiting recess 152 at the bottom of the working member 15 functions to restrict the rolling element 14 to smoothly move in the guide path 161.

(g) Completion of Rewind Procedure:

-   -   Please refer to FIGS. 1, 2, and 4G at the same time. When the         cable 18 being pulled out in two directions is released again,         the working member 15 is caused by the elastic force of the         first elastic element 12 to turn clockwise again, and the         rolling element 14 is brought to smoothly move in the inner path         section 161 b again.

Please refer to FIGS. 5 and 6 that are exploded perspective views of an automatically lockable cable rewinding structure according to a second embodiment of the present invention in an upside-down and a normal position, respectively. As shown, the automatically lockable cable rewinding structure in the second embodiment includes an upper case 21, a first elastic element 22, a rolling element 24, a length of cable 28, a working member 25, and a lower case 26.

The upper case 21 is provided on an inner side with an axially inward projected first locating element 211. As can be clearly seen from FIGS. 5 and 6, the lower case 26 is provided on a bottom at a predetermined position with a radially extended limiting recess 262. The limiting recess 262 is provided at radially outer and inner ends with transverse outer and inner slits 262 a, 262 c, respectively, and between the outer and inner ends with a longitudinal central slit 262 b, so that the rolling element 24 may stably roll to and fro in the limiting recess 262 along the central slit 262 b.

As can be seen from FIG. 5, the working member 25 is provided on a peripheral wall with a second locating element 251, and on a bottom with a guide path 252, along which the rolling element 24 moves. The first elastic element 22 is fixedly connected at an outer end to the second locating element 251 on the working member 25 and at an inner end to the first locating element 211 on the upper case 21. The guide path 252 is divided into a locking section 252 a, an inner path section 252 b, an outer path section 252 c, and a plurality of transition sections 252 d located at predetermined positions between the inner path section 252 b and the outer path section 252 c. The locking section 252 a is adjacent to a beginning of the inner path section 252 b.

The automatically lockable cable rewinding structure in the second embodiment of the present invention is structurally similar to the first embodiment, except that the limiting recess is provided on the lower case instead of the working member, and the guide path is provided on the working member instead of the lower case. Meanwhile, the second embodiment operates in the same procedures as that in a third embodiment of the present invention, which will be described in details below, except that the cable 28 is pulled out in two directions.

Please refer to FIGS. 7 and 8 that are exploded perspective views of an automatically lockable cable rewinding structure according to a third embodiment of the present invention in an upside-down and a normal position, respectively; and to FIG. 9 that is an assembled view of FIG. 8. As shown, the automatically lockable cable rewinding structure in the third embodiment includes an upper case 31, a first elastic element 32, a rolling element 34, a length of cable 38, a working member 35, and a lower case 36. Generally speaking, the third embodiment is structurally similar to the second embodiment, except that the cable 38 can be pulled out of the rewinding structure only in one direction instead of two opposite directions.

The upper case 31 is provided on an inner side with an axially inward projected first locating element 311. As can be clearly seen from FIGS. 7 and 8, the lower case 36 is provided on a bottom at a predetermined position with a radially extended limiting recess 362. The limiting recess 362 is provided at radially outer and inner ends with transverse outer and inner slits 362 a, 362 c, respectively, and between the outer and the inner end with a longitudinal central slit 362 b, so that the rolling element 34 may stably roll to and fro in the limiting recess 362 along the central slit 362 b.

As can be seen from FIG. 7, the working member 35 is provided on a top at a predetermined position with a second locating element 351, and on a bottom with a guide path 352, along which the rolling element 34 moves. The first elastic element 32 is fixedly connected at an outer end to the second locating element 351 on the working member 35 and at an inner end to the first locating element 311 on the upper case 31. The guide path 352 is divided into a locking section 352 a, an inner path section 352 b, an outer path section 352 c, and a plurality of transition sections 352 d located at predetermined positions between the inner path section 352 b and the outer path section 352 c. The locking section 352 a is adjacent to a beginning of the inner path section 352 b.

Please refer to FIGS. 8 and 9. To assemble the automatically lockable cable rewinding structure of the third embodiment, wind the cable 38 around the top of the working member 35, such that the cable 38 can be pulled out of the rewinding structure in only one direction, and position the rolling element 34 in the limiting recess 362. When the working member 35 is connected to the lower case 36, make sure the rolling element 34 is seated in the guide path 352 at the bottom of the working member 35. Finally, fixedly connect the upper case 31 to the lower case 36.

With the above arrangements, the automatically lockable cable rewinding structure according to the third embodiment of the present invention is able to successfully lock or rewind the cable 38 through the following operating procedures.

(a) Pull Procedure 1:

-   -   Please refer to FIGS. 7, 8, and 10A at the same time. It is         noted the cable 38 can be pulled out of the assembled upper and         lower cases 31, 36 in only one direction. When the cable 38 is         pulled out at an end thereof, the working member 35 is caused to         turn counterclockwise, and the rolling element 34 is caused to         move in the inner path section 352 b.

(b) Pull Procedure 2:

-   -   Please refer to FIGS. 7, 8, and 10B at the same time. When the         cable 38 is kept pulling out in the same direction to turn the         working member 35 counterclockwise, the rolling element 34 would         move from the inner path section 352 b through the transition         sections 352 d into the outer path section 352 c. At this point,         the limiting recess 362 at the bottom of the lower case 36         functions to restrict the rolling element 34 to smoothly move in         the guide path 352.

(c) Pull Procedure 3:

-   -   Please refer to FIGS. 7, 8, and 10C at the same time. When the         cable 38 is kept pulling out in the same direction to turn the         working member 35 counterclockwise, the rolling element 34 would         move in the outer path section 352 c.

(d) Lock Procedure 1:

-   -   Please refer to FIGS. 7, 8, and 10D at the same time. When the         cable 38 being pulled out in the same direction is released, the         working member 35 is caused by the first elastic element 32 to         turn clockwise, and the rolling element 34 is caused to move         from the outer path section 352 c through the transition         sections 352 d. At this point, the limiting recess 362 at the         bottom of the lower case 36 functions to restrict the rolling         element 34 to smoothly move in the guide path 352 to the locking         section 352 a.

(e) Lock Procedure 2:

-   -   Please refer to FIGS. 7, 8, and 10E at the same time. When the         cable 38 being pulled out in the same direction is released, the         rolling element 34 is affected by an elastic force of the first         elastic element 32 to stop in the locking section 352 a.

(f) Rewind Procedure:

-   -   Please refer to FIGS. 7, 8, and 10F at the same time. When the         released cable 38 is slightly pulled out in the same direction         again, the working member 35 is caused to turn counterclockwise         again, and the rolling element 34 is caused to move from the         locking section 352 a through the transition sections 352 d into         the inner path section 352 b. At this point, the limiting recess         362 at the bottom of the lower case 36 functions to restrict the         rolling element 34 to smoothly move in the guide path 352.

(g) Completion of Rewind Procedure:

-   -   Please refer to FIGS. 7, 8, and 10G at the same time. When the         cable 38 being pulled out in the same direction is released         again, the working member 35 is caused by the elastic force of         the first elastic element 32 to turn clockwise again, and the         rolling element 34 is brought to smoothly move in the inner path         section 352 b again.

Please refer to FIGS. 11 and 12 that are exploded perspective views of an automatically lockable cable rewinding structure according to a fourth embodiment of the present invention in a normal and an upside-down position, respectively. As shown, the automatically lockable cable rewinding structure in the fourth embodiment includes an upper case 41, a first elastic element 42, a rolling element 44, a length of cable 48, a working member 45, and a lower case 46.

The upper case 41 is provided on an inner side with an axially inward projected first locating element 411, and the lower case 46 is provided on an inner side with a guide path 461, along which the rolling element 44 moves. The guide path 461 is divided into a locking section 461 a, an inner path section 461 b, an outer path section 461 c, and a plurality of transition sections 461 d located at predetermined positions between the inner path section 461 b and the outer path section 461 c. The locking section 461 a is adjacent to a beginning of the inner path section 461 b.

The working member 45 is provided on a top at a predetermined position with a second locating element 451, and on a bottom at a predetermined position with a radially extended limiting recess 452. The first elastic element 42 is fixedly connected at an outer end to the second locating element 451 on the working member 45 and at an inner end to the first locating element 411 on the upper case 41. The limiting recess 452 is provided at radially outer and inner ends with transverse outer and inner slits 452 a, 452 c, respectively, and between the inner and outer ends with a longitudinal central slit 452 b, so that the rolling element 44 may stably roll to and fro in the limiting recess 452 along the central slit 452 b.

The automatically lockable cable rewinding structure in the fourth embodiment of the present invention is generally structurally similar to the third embodiment, except that the guide path is provided on the lower case instead of the working member, and the limiting recess is provided on the working member instead of the lower case. Meanwhile, the fourth embodiment operates in the same procedures as that in the first embodiment of the present invention, except that the cable 48 is pulled out in only one direction.

The following are some of the advantages and effects of the automatically lockable cable rewinding structure of the present invention, compared with the prior art:

-   -   (1) When the rolling element passes through the transition         sections, which have a height different from that of the inner         and outer path sections, the portions of the limiting recess at         two opposite sides of the central slit are automatically         inclined by an angle sufficient to provide a buffer effect, so         that the rolling element can always smoothly roll through the         guide path.     -   (2) In some embodiments of the present invention, the guide path         is provided on the inner side of the lower case, and the         limiting recess is provided on the bottom of the working member         to ensure that the rolling element always smoothly moves in the         guide path. Since the lower cases for most cable rewinding         structures generally have a standardized thickness that is         usually not too large, the provision of the limiting recess on         the working member to guide the movement of the rolling element         as disclosed in the present invention allows the limiting recess         to provide better effect than that in the prior art.     -   (3) The reaction forces applied by the portions of the limiting         recess at two opposite sides of the central slit to the rolling         element are of an elastic force, which is helpful in reducing         the wearing of the guide path caused by the movement of the         rolling element in the guide path.     -   (4) The automatically lockable cable rewinding structure of the         present invention has simple structure to allow easy manufacture         and assembly at reduced labor and material costs. That is, the         present invention may be completed without too many complicate         machining and assembling procedures.

The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

1. An automatically lockable cable rewinding structure, comprising an upper case, a working member, and a lower case; the upper case being provided on an inner side with an axially inward extended first locating element; the working member being provided at a predetermined position with a second locating element, and on a bottom with a guide path for a rolling element to move therein; a length of cable being wound around an outer periphery of the working member, and a first elastic element being connected at an inner end to the first locating element on the upper case and at an outer end to the second locating element on the working member; and the lower case being provided on a bottom at a predetermined position with a radially extended limiting recess, which is formed at radially inner and outer ends with transverse inner and outer slits, respectively, and between the inner and the outer end with a longitudinal central slit, so that the rolling element is able to stably roll to and fro in the limiting recess along the central slit.
 2. The automatically lockable cable rewinding structure as claimed in claim 1, wherein the guide path is divided into a locking section, an inner path section, an outer path section, and a plurality of transition sections located at predetermined positions between the inner and the outer path section; and the locking section being located adjacent to a beginning of the inner path section.
 3. The automatically lockable cable rewinding structure as claimed in claim 1, wherein the cable is wound around the working member in such a manner that the cable may be pulled out of the closed upper and lower cases in two opposite directions.
 4. The automatically lockable cable rewinding structure as claimed in claim 1, wherein the cable is wound around the working member in such a manner that the cable may be pulled out of the closed upper and lower cases in only one direction.
 5. An automatically lockable cable rewinding structure, comprising an upper case, a working member, and a lower case; the upper case being provided on an inner side with an axially inward extended first locating element; the lower case being provided on an inner side with a guide path for a rolling element to move therein; and the working member being provided at a predetermined position with a second locating element, and on a bottom at a predetermined position with a radially extended limiting recess; a length of cable being wound around an outer periphery of the working member, and a first elastic element being connected at an inner end to the first locating element on the upper case and at an outer end to the second locating element on the working member; and the limiting recess being formed at radially inner and outer ends with transverse inner and outer slits, respectively, and between the inner and the outer end with a longitudinal central slit, so that the rolling element is able to stably roll to and fro in the limiting recess along the central slit.
 6. The automatically lockable cable rewinding structure as claimed in claim 5, wherein the guide path is divided into a locking section, an inner path section, an outer path section, and a plurality of transition sections located at predetermined position between the inner and the outer path section; and the locking section being located adjacent to a beginning of the inner path section.
 7. The automatically lockable cable rewinding structure as claimed in claim 5, wherein the cable is wound around the working member in such a manner that the cable may be pulled out of the closed upper and lower cases in two opposite directions.
 8. The automatically lockable cable rewinding structure as claimed in claim 5, wherein the cable is wound around the working member in such a manner that the cable may be pulled out of the closed upper and lower cases in only one direction. 